Authentication & logon
How Windows turns credentials into authenticated sessions, security contexts, and usable access tokens.
Guided paths in this branch
Follow a short sequence step by step. Each path links to the first topic; use Read next on each page to continue.
Authentication path
From Winlogon through LSASS to Kerberos/NTLM and crypto plumbing.
Step 1 of 6 in this path
Official Microsoft docs
Closest official references related to this topic on Microsoft Learn.
Why it matters
Authentication is where identity enters the system. It explains why tokens exist, why LSASS matters, and why logs and sessions reflect specific users and services.
Mental model
Logon is a pipeline: credentials are gathered, an authentication package validates them, Windows creates a logon session, and the resulting security context becomes a token.
Windows building blocks
Names and paths you can look for in Task Manager, Explorer, or documentation.
- Processlsass.exe
Hosts LSA and authentication packages
Go one level deeper
Extra detail for readers who want more precision before opening a child topic.
- Credential Guard moves secrets into an isolated VTL when enabled.
- CloudAP and other packages extend AAD/Windows Hello flows.
How it works
- 1Winlogon and related UI components gather or broker credentials.
- 2LSASS chooses or hosts authentication packages such as Kerberos or NTLM.
- 3On success, Windows creates logon state and tokens that later processes and threads use.
Key terms
- LSASS
- Local Security Authority Subsystem Service, the protected process that enforces local security policy and authentication.
- SAM
- Security Accounts Manager, the local account database for machine-local identities.
- Authentication package
- A protocol or provider such as Kerberos or NTLM used to validate identity.
Signing in and opening a network share later
The initial logon produces security context and cached credential material that later let Windows access resources without asking for the password every time.
Common misconception
Authentication is not the same as authorization. Logon proves identity; later access checks still decide what that identity may actually do.
Go deeper
Winlogon, LogonUI, and session sign-in
The visible and semi-visible path from secure attention to a fully signed-in session.
LSASS, SAM, and local security policy
The protected security process and data stores behind local accounts and policy decisions.
Kerberos, NTLM, and authentication packages
How Windows chooses and uses protocol packages to validate identities.
CNG, Schannel & crypto plumbing
How Windows centralizes algorithms, keys, and TLS for services and applications.
You should read next
Ranked from your current topic, related links, branch depth, and any active guided path.
intermediate
Winlogon, LogonUI, and session sign-in
The visible and semi-visible path from secure attention to a fully signed-in session.
Next step in your guided path
intermediate
LSASS, SAM, and local security policy
The protected security process and data stores behind local accounts and policy decisions.
Go deeper in this branch
intermediate
Kerberos, NTLM, and authentication packages
How Windows chooses and uses protocol packages to validate identities.
Go deeper in this branch
Related topics
Access tokens
SIDs, privileges, impersonation, and the identity payload every process carries.
Session Manager, Winlogon, and the shell
The early user-mode path from system process creation to an interactive desktop.
Providers & channels
Who emits events and where those records are routed inside Windows logging.